Transcript for Tamerlan Tsarnaev's Trip Home to Russia Raises Questions for FBI

As investigators peered deeply into the lives of the bombing suspects they will be taking -- very hard look at what happened in a remote and dangerous part of Russia visited not long ago it Brian Ross reported. By the older brother he apparently came back a changed man and ABC's -- Roddy -- is there tonight. Last year Collins. A restive region home -- Islamist uprising. Investigators now want to learn if it was during that trip that he became radicalized. But family who saw him then told us today based on -- signs of extremism. -- -- -- -- -- There was no feeling that he could be his son said he's not possible -- she showed us photos of the suspect as young boys. But which they were very kind employees he says that -- and came here to renew his passport. Young says he stayed to trained as a boxer. They -- Cumberland -- in the city's central mosque on Fridays but denied that they fought over religion is evaluating stents put it we were debating what did she says but not fighting. Cumberland spend six months and -- done. Relatives say he visited Chechnya also home to Islamist militants at least three times. To visit family and also choosing decline pulled from the Chechen capital younger brother jewel heart was expected to visit -- -- done in May. -- uncle told us he's a great progress survival job cuts Oakland's doable we'll call he can tell us what really happened I said curator idea ABC news -- -- -- it's not.

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